The Tcpdump Group git mirrors - tcpdump/blob - print-sll.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21 #ifndef lint
  22 static const char rcsid[] =
  23     "@(#) $Header: /tcpdump/master/tcpdump/print-sll.c,v 1.4 2001-01-15 00:33:59 guy Exp $ (LBL)";
  24 #endif
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/time.h>
  32 #include <sys/socket.h>
  33
  34 struct mbuf;
  35 struct rtentry;
  36
  37 #include <netinet/in.h>
  38
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include <pcap.h>
  42
  43 #include "interface.h"
  44 #include "addrtoname.h"
  45 #include "ethertype.h"
  46
  47 #include "ether.h"
  48 #include "sll.h"
  49
  50 const u_char *packetp;
  51 const u_char *snapend;
  52
  53 static inline void
  54 sll_print(register const struct sll_header *sllp, u_int length)
  55 {
  56         u_short halen;
  57
  58         switch (ntohs(sllp->sll_pkttype)) {
  59
  60         case LINUX_SLL_HOST:
  61                 (void)printf("< ");
  62                 break;
  63
  64         case LINUX_SLL_BROADCAST:
  65                 (void)printf("B ");
  66                 break;
  67
  68         case LINUX_SLL_MULTICAST:
  69                 (void)printf("M ");
  70                 break;
  71
  72         case LINUX_SLL_OTHERHOST:
  73                 (void)printf("P ");
  74                 break;
  75
  76         case LINUX_SLL_OUTGOING:
  77                 (void)printf("> ");
  78                 break;
  79
  80         default:
  81                 (void)printf("? ");
  82                 break;
  83         }
  84
  85         /*
  86          * XXX - check the link-layer address type value?
  87          * For now, we just assume 6 means Ethernet.
  88          * XXX - print others as strings of hex?
  89          */
  90         halen = ntohs(sllp->sll_halen);
  91         if (halen == 6)
  92                 (void)printf("%s ", etheraddr_string(sllp->sll_addr));
  93
  94         if (!qflag)
  95                 (void)printf("%s ", etherproto_string(sllp->sll_protocol));
  96         (void)printf("%d: ", length);
  97 }
  98
  99 /*
 100  * This is the top level routine of the printer.  'p' is the points
 101  * to the ether header of the packet, 'h->tv' is the timestamp,
 102  * 'h->length' is the length of the packet off the wire, and 'h->caplen'
 103  * is the number of bytes actually captured.
 104  */
 105 void
 106 sll_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
 107 {
 108         u_int caplen = h->caplen;
 109         u_int length = h->len;
 110         register const struct sll_header *sllp;
 111         u_short pkttype;
 112         struct ether_header ehdr;
 113         u_short ether_type;
 114         u_short extracted_ethertype;
 115
 116         ts_print(&h->ts);
 117
 118         if (caplen < SLL_HDR_LEN) {
 119                 /*
 120                  * XXX - this "can't happen" because "pcap-linux.c" always
 121                  * adds this many bytes of header to every packet in a
 122                  * cooked socket capture.
 123                  */
 124                 printf("[|sll]");
 125                 goto out;
 126         }
 127
 128         sllp = (const struct sll_header *)p;
 129
 130         /*
 131          * Fake up an Ethernet header for the benefit of printers that
 132          * insist on "packetp" pointing to an Ethernet header.
 133          */
 134         pkttype = ntohs(sllp->sll_pkttype);
 135
 136         /* The source address is in the packet header */
 137         memcpy(ehdr.ether_shost, sllp->sll_addr, ETHER_ADDR_LEN);
 138
 139         if (pkttype != LINUX_SLL_OUTGOING) {
 140                 /*
 141                  * We received this packet.
 142                  *
 143                  * We don't know the destination address, so
 144                  * we fake it - all 0's except that the
 145                  * bottommost bit of the bottommost octet
 146                  * is set for a unicast packet, all 0's except
 147                  * that the bottommost bit of the uppermost
 148                  * octet is set for a multicast packet, all
 149                  * 1's for a broadcast packet.
 150                  */
 151                 if (pkttype == LINUX_SLL_BROADCAST)
 152                         memset(ehdr.ether_dhost, 0xFF, ETHER_ADDR_LEN);
 153                 else {
 154                         memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
 155                         if (pkttype == LINUX_SLL_MULTICAST)
 156                                 ehdr.ether_dhost[0] = 1;
 157                         else
 158                                 ehdr.ether_dhost[ETHER_ADDR_LEN-1] = 1;
 159                 }
 160         } else {
 161                 /*
 162                  * We sent this packet; we don't know whether it's
 163                  * broadcast, multicast, or unicast, so just make
 164                  * the destination address all 0's.
 165                  */
 166                 memset(ehdr.ether_dhost, 0, ETHER_ADDR_LEN);
 167         }
 168
 169         if (eflag)
 170                 sll_print(sllp, length);
 171
 172         /*
 173          * Some printers want to get back at the ethernet addresses,
 174          * and/or check that they're not walking off the end of the packet.
 175          * Rather than pass them all the way down, we set these globals.
 176          */
 177         snapend = p + caplen;
 178         /*
 179          * Actually, the only printers that use packetp are print-arp.c
 180          * and print-bootp.c, and they assume that packetp points to an
 181          * Ethernet header.  The right thing to do is to fix them to know
 182          * which link type is in use when they excavate. XXX
 183          */
 184         packetp = (u_char *)&ehdr;
 185
 186         length -= SLL_HDR_LEN;
 187         caplen -= SLL_HDR_LEN;
 188         p += SLL_HDR_LEN;
 189
 190         ether_type = ntohs(sllp->sll_protocol);
 191
 192         /*
 193          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 194          * packet type?
 195          */
 196         extracted_ethertype = 0;
 197         if (ether_type <= ETHERMTU) {
 198                 /*
 199                  * Yes - what type is it?
 200                  */
 201                 switch (ether_type) {
 202
 203                 case LINUX_SLL_P_802_3:
 204                         /*
 205                          * Ethernet_802.3 IPX frame.
 206                          */
 207                         ipx_print(p, length);
 208                         break;
 209
 210                 case LINUX_SLL_P_802_2:
 211                         /*
 212                          * 802.2.
 213                          * Try to print the LLC-layer header & higher layers.
 214                          */
 215                         if (llc_print(p, length, caplen, ESRC(&ehdr),
 216                             EDST(&ehdr), &extracted_ethertype) == 0)
 217                                 goto unknown;   /* unknown LLC type */
 218                         break;
 219
 220                 default:
 221                 unknown:
 222                         /* ether_type not known, print raw packet */
 223                         if (!eflag)
 224                                 sll_print(sllp, length + SLL_HDR_LEN);
 225                         if (extracted_ethertype) {
 226                                 printf("(LLC %s) ",
 227                                etherproto_string(htons(extracted_ethertype)));
 228                         }
 229                         if (!xflag && !qflag)
 230                                 default_print(p, caplen);
 231                         break;
 232                 }
 233         } else if (ether_encap_print(ether_type, p, length, caplen,
 234             &extracted_ethertype) == 0) {
 235                 /* ether_type not known, print raw packet */
 236                 if (!eflag)
 237                         sll_print(sllp, length + SLL_HDR_LEN);
 238                 if (!xflag && !qflag)
 239                         default_print(p, caplen);
 240         }
 241         if (xflag)
 242                 default_print(p, caplen);
 243  out:
 244         putchar('\n');
 245 }